In County of Monterey v. W. W. Leasing Unlimited (1980) 109 Cal.App.3d 636, the defendant landowner attempted to introduce undisclosed comparable sales during the direct examination of its valuation expert, and the trial court sustained the plaintiff county's objection thereto. (W.W. Leasing, supra, 109 Cal.App.3d at p. 643.) Thereafter, the defendant attempted to persuade the trial court that the data was admissible on cross-examination of the plaintiff's valuation expert and in rebuttal. (Ibid.) The court allowed limited cross-examination of the plaintiff's expert as to whether he had considered the subject sales data but refused to allow testimony concerning the data in rebuttal. (Ibid.) In affirming the trial court's ruling, the Court of Appeal acknowledged that the exclusionary provisions of section 1258.280 apply only to the presentation of undisclosed data during the offering party's case-in-chief, but found that it was "clear from the Law Revision Commission's comments ... that the concept of 'rebuttal' is not to be used in derogation of the requirement that data be exchanged pursuant to the prescribed procedures." (W.W. Leasing, at p. 644.) The court further explained that "it is well established that rebuttal evidence does not properly consist of additional opinion evidence concerning valuation. Rather, it must be concerned with and address new matter brought out by the opposing party. " (Id. at pp. 644-645.) The court concluded that the "comparables" the defendant sought to introduce constituted "improper rebuttal evidence in that they were simply additional evidence on the question of value." (Id. at p. 645.)